Introduction of Alien Tree Species and its Influence on Floristical Composition and Vegetation Structure of Acidophilous Oak Forests: The Experimental Plots in the Zielonka Forest

In 1879 Schwappach first established 54 experimental forest plots on habitat of acidophilous oak forest Calamagrostio-Quercetum in the Zielonka Forest near Poznań, on which 20 exotic tree species were cultivated. Until this day 32 of the mentioned forest sites have been preserved and today only 9 species are present there. The aim of the study was to determine actual condition of the experimental plots, a description of their flora and vegetation, as well as a comparison with other test plots situated in the direct neighbourhood. Basing on 63 phytosociological relevés, an influence of exotic species plantings on the structure of vegetation and local biodiversity was assessed. Floristic richness of both experimental plots (88 species), as well as their direct neighbourhood (68) was recognised, along with the geographical-historical groups spectrum and species affiliation to phytosociological classes

LICHENS GROWING ALONG THE ROAD BETWEEN WĄGROWIECAND MARGONIN (WIELKOPOLSKA REGION)

The subject of the investigation was the lichen biota along road No 190 from Margonin to Wągrowiec (about 20 km). The field studies were conducted on 30 randomly chosen sites, situated 500-1.000 m apart from each other. In each of them the lichens were collected from 4-6 trees on either side of the road, and from other habitats: concrete poles, fallen branches and the soil. Presence of 61 taxa was stated, among them 18 under legal protection and/or endangered in Poland. They include Cladonia mitis, Collema auriforme, Evernia prunastri, Melanelia exasperatula, Opegrapha rufescens, O. varia, Parmelina tiliacea, Peltigera canina, Pertusaria coccodes, Phaeophyscia chloantha, Physcia aipolia, Physconia distorta, Pleurosticta acetabulum, Punctelia subrudecta, Ramalina farinacea, R. fraxinea, R. pollinaria and Xanthoparmelia verruculifera. The above mentioned species, the most valuable from the point of view of nature protection, tended to concentrate around Margonin. On a old lime alley close to Wągrowiec the lichen biota was poor, and only the most common taxa (Hypocoenomyce scalaris, Lepraria incana, Phaeophyscia orbicularis, Trapeliopsis flexuosa and Xanthoria parietina ) were identified there. It may be related to higher air pollution in the vicinity of the town of Wągrowiec. Notably, old trees, even when growing along quite busy roads, may still host protected and endangered lichens in the prevailing open, agricultural landscape of Wielkopolska

Taxonomic position of Pinus uliginosa Neumann as related to other taxa of Pinus mugo complex

Studies on taxonomic position of Pinus uliginosa Neumann, P. uncinata Ram. and P. mugo Turra, indicate a significant specificity of P. uliginosa population from Wielkie Torfowisko Batorowskie Peat Bog. Pinus uncinata in respect of genetic similarity is close to Pinus mugo Turra populations from the Tatra Mts. The time of divergence of P. uliginosa from the common ancestor, taking into account Nei's genetic distances, is twice as long as in the case of Pinus uncinata. In the view of the results the supposition that Pinus uliginosa from Wielkie Torfowisko Batorowskie Peat Bog is a marginal population of P. uncinata can be excluded, because of their significant difference in genetic structure. The presumable reasons of specificity of P. uliginosa population are disscused